

def f1():
    print 'f1'
    def f2():
        print 'f2'
        def f3():
            print "f3"
        return f3
    return f2

f = f1  #no print out

print f 

f = f() 

print f 

f = f() 

print f 

print f() 

f = f()  

print f 

